It is known in the state-of-the-art to measure the flow velocity or the mass or volumetric flow rate of a liquid or gaseous medium by means of a semiconductor module on which a thermal source and a suitable temperature sensing means are arranged. The flow leads to a change in the temperature distribution of the thermal source which can be measured using the temperature sensing means.
However, semiconductor modules of this kind are very sensitive. When in contact with certain liquids or gases, such modules can be easily contaminated or damaged. Furthermore, mechanical loads may damage the module. In some applications, the problem may further arise, that the medium that is to be measured can be contaminated by the semiconductor module. Therefore, the semiconductor modules have to be separated from the medium by means of protective layers, for instance, which is difficult to achieve however.
Particularly in cases where the flow sensor is to be arranged inside the body of a body of a patient further precautions have to be taken to assure that the sensor and its materials do not pose a risk for the patient.